From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8764DC3F2D7 for ; Tue, 3 Mar 2020 17:52:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 578E820870 for ; Tue, 3 Mar 2020 17:52:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583257962; bh=YJBfCqSByjSFxgGWmbPxYXFHCKKUp9aukC1dgwZBS04=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vAbYZINCbMgYiLk1510G3M2Bn4ul9aYoOcgt1Dp+vmDIWkk/Z9Fg6Hc11qhWxEMxN Gsch/uSWeeCh5yaKqemxDMhGFu5OYZo9ARlASsrnbCaoi0R1Pd6fArr5R9dv3dUcgA xC1ZXOrGmPBrRKJgxzLV9gdPScndtnu4h6PESros= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732198AbgCCRwk (ORCPT ); Tue, 3 Mar 2020 12:52:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:32948 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732178AbgCCRwj (ORCPT ); Tue, 3 Mar 2020 12:52:39 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A5FBC20728; Tue, 3 Mar 2020 17:52:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583257959; bh=YJBfCqSByjSFxgGWmbPxYXFHCKKUp9aukC1dgwZBS04=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Or/KiS3Eqx7fpoSv+WG6K6GdwKh9a5HnH05XtiY66ytQxm6167knty2VYdP5d0JQ2 ZJsCJABwCdZJSIOQyeJZzrwFwkRijc/b1sRmD4xfKikUAvslJi0zzby5WbWzxANdYm 01ibqKozKVIX3Q3vODi3P2Qa6/ywZdA1Y05tSULo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dmitry Osipenko , "David S. Miller" Subject: [PATCH 5.4 010/152] nfc: pn544: Fix occasional HW initialization failure Date: Tue, 3 Mar 2020 18:41:48 +0100 Message-Id: <20200303174303.693587076@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200303174302.523080016@linuxfoundation.org> References: <20200303174302.523080016@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dmitry Osipenko [ Upstream commit c3331d2fe3fd4d5e321f2467d01f72de7edfb5d0 ] The PN544 driver checks the "enable" polarity during of driver's probe and it's doing that by turning ON and OFF NFC with different polarities until enabling succeeds. It takes some time for the hardware to power-down, and thus, to deassert the IRQ that is raised by turning ON the hardware. Since the delay after last power-down of the polarity-checking process is missed in the code, the interrupt may trigger immediately after installing the IRQ handler (right after the checking is done), which results in IRQ handler trying to touch the disabled HW and ends with marking NFC as 'DEAD' during of the driver's probe: pn544_hci_i2c 1-002a: NFC: nfc_en polarity : active high pn544_hci_i2c 1-002a: NFC: invalid len byte shdlc: llc_shdlc_recv_frame: NULL Frame -> link is dead This patch fixes the occasional NFC initialization failure on Nexus 7 device. Signed-off-by: Dmitry Osipenko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/nfc/pn544/i2c.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/nfc/pn544/i2c.c +++ b/drivers/nfc/pn544/i2c.c @@ -225,6 +225,7 @@ static void pn544_hci_i2c_platform_init( out: gpiod_set_value_cansleep(phy->gpiod_en, !phy->en_polarity); + usleep_range(10000, 15000); } static void pn544_hci_i2c_enable_mode(struct pn544_i2c_phy *phy, int run_mode)